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dalutong writes "BBC News has an article detailing NASA's replacement for the much-loved Hubble telescope. The $4.5 billion telescope will be placed in orbit 1.5 million km from Earth and will be almost three times the size of the Hubble. It is set to launch in 2013. They also plan to service the Hubble in 2008."

I recall that the Orion program which is currently under development will have the capability to do the job. It is slated to replace the shuttle and also have the ability to reach the moon. One of the goals was to be able to do a service mission of the JWT far far away. More info here. http://www.nasa.gov/mission_pages/constellation/ma in/index.html/ [nasa.gov]

I recall that the Orion program which is currently under development will have the capability to do the job.

That's an interesting question though. From what I can see, the Orion vehicle is basically a larger and more modern version of the old Apollo vehicles. Although larger in crew carrying capcity, its going to be very cramped living in that space. You'll need to launch a second cargo vehicle rand rendezvous with it, unless the repairs can be done with a portable toolkit and without the benefit of th

Ground based telescopes are good only for light that is not filtered by the atmosphere. There is a whole lot of spectrum outside it. The JWST targets the infra-red wavelengths, which would be much harder to do with an atmosphere above it

There is no "dark side" of the moon, only a side that never faces Earth. Both sides get their fair share of sunlight during the Lunar day (about 29 earth days, about half of that time of which would be spent in sunlight regardless of which side you're on). Putting the telescope on the "opposite" side though would be very bad. For it to receive radio communications some type of repeater would be necessary, otherwise you're never in LOS with Earth to send back or receive signals. It'd be far more efficient

The dark side of moon still gets sunlight. The moon is tidal locked with the Earth so we always see the same side of the moon but that does not mean that the part we can't see isn't still receiving sunlight.

And of course we could put a telescope on the moon. But that's a lot more work then just putting something into orbit. Putting something in orbit removes the whole part of dealing with a landing and unloading and setting up of the telescope.

A number of reasons:The biggest drawback is dust. We just don't know how lunar dust would behave, or how it would affect the optics. Also, the cost of constructing anything on the moon is quite high, higher even than for a free-flying space mission. Another problem is that it reduces observation time - in space you can pretty much point anywhere except at the sun. On the lunar surface, you have the moon in the way of half the sky or more at any given time - and there is no "dark" side, just the far side

Nice replies. I do understand that the "dark side" of the moon gets sunlight. I suppose I was using an idiomatic expression which shouldn't require explanation. And/or I've listened to too much floyd....

Because the moon orbits the Earth and therefore can't focus on a single point in space for long periods due to the Earth obscuring the view (a fault with the Hubble as well). The JWST can gather light from a single point, uninterrupted, for months if desired. There are other reasons as well, but this one alone is enough of a deal killer.

In addition to what the poster above me says about the atmosphere and spectrum of light, I'd like to point out...

$5 Billion dollars DOES seem like a lot. But look at the U.S. Budget in the last decade. Look at the money we've essentially THROWN AWAY. By comparison, $5 billion for an advancement of science seems rather reasonable, or at the very least, reasonable by comparison.

The average cost of each war the US engages in ends up being around $600 billion (after adjusting each one for inflation). We'll just have to complete the next war in 119/120ths of the time and the cost of the new telescope is covered:)

JWST will provide diffraction-limited images at 2 micron. It will have imaging and spectrographic capabilities in the near and mid-IR -- everything from 6000AA out to 27micron with the mid-IR imager and spectrograph (MIRI). StSci has a JWST primer online here [stsci.edu] (pdf link).

The imaging will be near infrared with particular capability near 2 microns, but the 5 micron capability is alos of interest. There is also a smaller camera working from 5 to 27 microns. This is mid-infrared. The resolution of this instrument will not be so good because of the longer wavelength. The Keck Telescope can get better image quality. But what it will have is spectroscopic capability and much greater sensitivity. We've gotten quite alot of milage out of the much smaller Spitzer Space Telescope using it's 5--30 micron spectrograph. This new instrument should really open things up, allowing us to analyse stars in galaxies as they were when the universe was 12 billion years younger. All telescopes can be considered time machines, but this one is made to see some of the very first stars. You can read more about it here: http://www.stsci.edu/jwst/instruments/ [stsci.edu].--Rent solar power: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

IANAA, rather a laymen at best. However JWST is hardly news; anyone that bothers to browse nasa.gov knows about it. As a result I have also wondered about the choice of wavelength for this instrument.

The resolution of this instrument will not be so good because of the longer wavelength.

I don't want to hear that. Don't misunderstand; I don't begrudge a single dime spent on it. I take it on faith that those who know best are building something incredible. Analysis of the early universe is crucial to cosmology. I get it.

If all the money and drama of NASA produced nothing but Hubble it has been worth it. NASA is billing JWST as Hubble's replacement. Is it? Really? Honestly?

You know, to me, NASA could do nothing but produce obscure scientific data that I would never comprehend, but I'd still support them spending my tax dollars more than the fuckers who waste my money on war. $4.5 billion for a precision scientific instrument is money well spent. $4.5 billion for waging war and murdering your fellow human beings is absolutely criminal.

I don't want to hear that. Don't misunderstand; I don't begrudge a single dime spent on it. I take it on faith that those who know best are building something incredible. Analysis of the early universe is crucial to cosmology. I get it.

There are two things happening here: The first is that the angular resolution of a telescope depends on the wavelegth. The longer the wavelength,
the lower the resolution. JWST is about four times larger than Hubble but it is optimized for a wavelength that is 4 times long

I was thinking about this the other day, if we ever are able to travel to a point in space thousands of light years away from Earth it would be interesting to turn something like this back on our own planet and see into its past.

If we have sophisticated enough technology to get that far away I'm sure they'll be a telescope powerful enough to witness actual events as they unfold on the surface.

You'd have to take time to travel to that distance so the advantage is erased. I am interested in incredibly large telescopes, which is what
you'd need to get that kind of detail. I've begun to wonder of the combined power production data from many solar power systems might be used
to study the Sun in more detail, especially helioseismology, or at night to monitor bolides and other bright transients.--You might be building the biggest telescope ever: http://mdsolar.blogspot.com/2007/01/slashdot-users -sel [blogspot.com]

While difficult, its much cheaper and easier to get hubble-style resolution in the optical range from ground.Dont forget that "hugely expensive" for a ground telescope is compareable to "dirt-cheap" for a space-based one.All 4 of the VLT telescopes were (IIRC) cheaper than a single hubble service mission. And OWL should be compareable to a modern space-telescope, too, for a fraction of the price (dont forget: its a tradeoff: better seeing vs "have to design a mirrror that can withstand the acceleraion and f

Your cost estimates are accurate, but the rest of your argument is total shit. Adaptive optics, WHEN it works (which is rarely, and with difficulty), can approach the angular resolution of HST in a VERY SMALL field of view. You cannot get 0.05 arcsec, diffraction limited images over a wide field of view, that is possible with HST.

"Designing a mirror to withstand a launch vehicle" is a problem that has been solved. And the only two current, viable telescope proposals for telescopes larger than 10m are the Thirty Metre Telescope (TMT [tmt.org]) and the Giant Magellan Telescope (GMT [gmto.org]). OWL is not a concept that is being taken very seriously...ESO certainly hasn't put its money where its mouth is.

Your final point, about not many lines in that part of the spectrum, belies a complete lack of understanding of what you are talking about. The UV (accessible with STIS, and the Cosmic Origins Spectrograph, which will fly on SM4 in late '08) are so full of lines that they overlap all over the place. See, for example, Morton (2003), ApJS, 149, 205, for a comprehensive list. At low redshift, lines of HI, OI, OVI, CIV, NV, CII, SiII, SII, FeII, NI...all are in the UV, in the STIS band. Furthermore, space is the ONLY place these wavelengths can be observed, because of the atmosphere is opaque to wavelengths shorter than about 3300 angstroms.

No. Terrestrial is catching up with Hubble in the visible, but terrestrial cannot see into the IR - full stop. SD0o there is much more untapped science in the IR than in the visible. Our preoccupation with the visible is highly speciesist. Anyway, you won't lose your pretty pictures of exploding galaxies: most of them are false colour or so highly processed as to amount to false colour.The cost of the JWST is about the same as two Stealth bombers or less than a a dozen Strike Fighters. While I know there is

Wow. Somebody at./ who actually knows his stuff outside linux/OS.Ok, i admit i trolled a bit with the "no interesting lines" part, (although i still have the oppinion that currently, infrared it much more interesting. Who cares about another star if one extrasolar planet after the other pops up?).And yes, adaptive optics arent a cure-for-all. But considering the sheer amount of light gathering capacity you can put up for a few 100 millions, its still a viable alternative.

"Now they intend to do it, but with a backup shuttle in orbit in case the first one gets into trouble."

That would be retarded; the most dangerous phases of the mission are launch and reentry, with a significantly lower risk of something going wrong while in orbit; something likely to either be so terrible you can't do anything or managable enough that you have a good long while to worry about it (e.g one of the tiles gets damaged at launch and you can't reenter safely, ala Columbia).

So no, it won't be in orbit, the backup shuttle will simply be ready to launch if needed.

Unfortunately you beat me to the punch on this one, I spent to much time double checking flight numbers and which OV's were going to be used. Sadly enough I use Wikipedia. I can't find shit on the NASA site half the time

but with a backup shuttle in orbit in case the first one gets into trouble.

Can you please site a source for this? Right now the software cannot actually support more than one shuttle in orbit at a time, if you look there has never been more than one up at a time. If there were this type of upgrade coming I could buy that story, but considering we're going to retire the fleet soon I don't see that as likely. I haven't installed any Aries specific equipment yet, but judging by the age of most of the shuttle specific equipment on the ground they're not going to do that level of a software rewrite for the shuttle when the fleets this close to retirement. Another issue with this statement is the shear altitude of the Hubble, well above ISS orbit. If we launched one into high orbit, and kept one at low orbit the one in low orbit simply wouldn't be able to reach the one in high orbit without landing for fuel anyways. Those things launch with their trajectories pretty much set and only do slight manuvering. STS-125 is the designated flight for Hubble servicing to be done by Atlantis, there is an as yet unnumbered contingency rescue flight, I don't think they number those unless they launch these days. They may put Discovery on the pad in ready position for rescue, but I seriously doubt they'll launch it unless they have to.

On another note:There are emergency two shuttle protocols. What that comes down to more or less is equipment time sharing.

I was quite the fervent supporter of the Hubble up until I attended a talk by Dr. Philip Stahl, from the Marshall Space Center, and optics technical lead on the new James Webb Space Telescope.

Yes, the JWST is an infrared telescope. But, as another post further down alludes to incorrectly (for which they were smacked down and corrected by someone else) the James Webb is able to see further back into the history of the universe than we have ever been able to observe. What started out as visible light all those billions of years ago (and billions of light years away) becomes red-shifted into the infrared as the universe expands and, in a nearly literal fashion, stretches out that incoming light.

So while the Hubble has been responsible for a lot of great science, and truly breath-taking images, we have the potential to do so much more and better understand our universe with the JWST. We haven't maxed out the potential of the Hubble (probably never would), and I would love to keep it, but if there's only enough to deploy the JWST (and it's already been pushed back by several years), or keep on servicing the Hubble, my vote would be in favour of the JWST.

we have the potential to do so much more and better understand our universe with the JWST

Wrong. We have the opportunity to do *different* things than we can with the Hubble. For example, unlike the JWST and ground-based scopes, the Hubble can see in the near-UV, which makes it possible to detect oxygen in nebulae, which is important for studying stellar evolution.

It is expected to be launched by the ESA in the second half of 2011, and will be operated in a Lissajous orbit around the Sun-Earth L2 Lagrangian point.

Let's hope they will agree on non-intersecating orbits for Gaia and JWST.

Gaia team: Hey! We were here first!JWST team: "Here"? You are oscillating all around the place!Gaia team: Ours is an elegant Lissajous orbit. What is yours?JWST team: We'll pwn the L2 point itself!Gaia team: No way! Our probe will intersect it in 13 days.JWST team: Metric days or imperi

As radiation travels from distant stars and passes through obstacles, gravitational lensing, dust clouds, etc., it loses energy and thus frequency eventually turning radiation from the gamma/x-ray spectrum into visible light then into infrared light. This new telescope will help us by giving us insights to some of the conditions that would be found very early on in the universe. Hubble and other similar land-based telescopes can't give us that insight because of not showing the infrared, the oldest informat

It is not exactly obstacles that cause the redshift, but rather the expansion of the universe. Dust can redden light, but this is really just subtracting blue light. Gravitational lensing is acromatic. In the gamma-rays, Compton scattering can shift photons to lower energy, but it does not preserve spectral features the way that the cosmological redshift does.

FYI, this project was originally started in 1987, but didn't get serious funding for over a decade. The final basic dimensions were selected in 2001, and detailed design and development of the many new technologies it will employ has been ongoing since then. Now it's finally begun construction. It was actually supposed to launch in 2011, but 2 years ago NASA decided to delay that two years to they could defray the costs out a little more.

When they start getting images from the JWST, they'll see a dude in a flowing white robe and beard waving his arms; lip readers will ultimately be able to make out the words "Let there be light!" in Hebrew.

Why does this need a sunshield at all? The article says that the telescope should be parked in the 2nd Lagrangian point L2, which is 1.5 Gm from the Earth and should be permanently shaded from sunlight. Isn't the whole point of sending something to L2 that it is not exposed to the sun? Also, how is the energy supply supposed to work? Anyone out there who can shed some light on these questions?

Earth only has 12000km diameter. Sun has 1.4 million km diameter.For earth to give shade, it would have to be closer than AU*(r_earth/r_sun), which is much closer than the lagrange point.Simply put: you would get a dark spot on the sun, but no complete cover.

First, the Sun is larger than the Earth, there is no permanently shaded point at L2. Second, the telescope will not actually be parked at L2, it will be in a halo orbit around L2. Third, it would be rather silly to park a solar powered vehicle in the shade, doncha think?Thus, the need for the sunshade.

The point of sending something to L2 is that it is still permanently close enough to Earth to make high bandwidth communications easy, while it is far enough from Earth to have an unobstructed view of nearly

Actually, you'd like to have it as some distance from Earth because the Earth is warm. At L2 you block both the Sun and Earth with the sun shield and so can make the telescope colder without extra shielding. This is not a big deal for Hubble but it is a big deal for infrared telescopes. Spitzer Space Telescope orbits the Sun on a trailing orbit to get away from the Earth's emissions.--Please help cool the Earth: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

Why does this need a sunshield at all? The article says that the telescope should be parked in the 2nd Lagrangian point L2, which is 1.5 Gm from the Earth and should be permanently shaded from sunlight. Isn't the whole point of sending something to L2 that it is not exposed to the sun? Also, how is the energy supply supposed to work? Anyone out there who can shed some light on these questions?

Something I've always wondered... how do the R&D costs compare to construction, testing, and launch of a satellite, or in this case, a space telescope? Wouldn't R&D be the hard part here, making the marginal cost of each additional spacecraft relatively small in comparison to the upfront cost?

It's my understanding that there's a substantial waiting list to use Hubble, and that a lot of very good research can't get done because telescope time is so limited. Time on JWST will probably be similarly limited... if we've spent $3.5B on this thing so far, why not put an extra $250M into it and get twice the benefit?

While I'm not the expert you asked for, I'd say because as Congress is in every generation (Congress isn't to be confused with a presidential party) - stingy on the purse strings. They were reluctant as hell to approve funding on the mission(s) to repair the Hubble - thats *repair* not send up another, which I would assume would be cheaper. So if it was a miracle to get a repair mission authorized, why would they approve even more money to send 2 up when they would be just as fine with letting the Hubble di

The telescope will orbit at a distance of 1.5m km - is that true? That puts it outside the orbit of the Moon does it not? About four times as far in fact? Wow, so this thing isn't designed to be serviced then. (wiki says Moon's apogee is 400,000km.

No, you are not being dumb. I noticed that a second after I read the summary too.
The weird part is that you posted your comment more than 4 hours after the article was posted, and it's hard to believe that no slashdotter noticed that before!

The last fancy telescope was named after an astrophysicist who made a significant contribution to our understanding of the universe, using the red shift to prove that the universe is indeed expanding, now commonly known as Hubble's law. The new telescope is named after an administrator. An important job, and done very well by the sounds of it, but it's not super-science. Am I the only one who sees the difference between running an agency and advancing the body of scientific knowledge? In 100 years time (heck, even today) who's name will we know?

It looks like James Webb was administor from 1961 to 1968, some very important years in spaceflight I'd say. The last moon walk was taken a year before I was born, so I don't have any direct experience with that era of space exploration. But I'm still amazed at how fast NASA moved from launching a satellite into orbit to putting men on the fricking moon and bringing them back safely. I wouldn't be surprised if this were in large part due to good leadership without which those accomplishments would have h

The new telescope is named after an administrator. An important job, and done very well by the sounds of it, but it's not super-science.

Ask any space historian to name the five people most responsible for the sucess NASA in the 60's and especially of the Apollo Project - and James Webb will almost certainly be on that list. Other candidates for that list are; Rocco Petrone, Chris Kraft, Joe Shea, Werhner Vonbraun, Maxime Faget, Robert Gilruth, George Low, George Mueller, General Sam Phillips, Dr. Farouk E

Sweet... 18 feet of desktop wallpaper-enhancing power! It would be great if it had a self-repairing mirror with a few extra panels installed, in case of close encounter with space dust at 18,000 miles per hour.

I'll avoid the tired old metric vs. american measurement arguments because (for once) this article referred to the telescope's distance from earth in metric from the start. But hey! Please can slashdot post articles with sensible SI prefixes in future?The telescope's going to be appx. 1.5Gm from earth. Much easier to keep track of distances in the solar system using Gm and Tm. (The moon is appx 0.4Gm from earth, earth is appx. 150Gm from the sun, etc etc).

..."JWST is named after James E Webb, Nasa Administrator during the Apollo lunar exploration era; he served from 1961 to 1968."
To add more evidence. Look, wikipedia!http://en.wikipedia.org/wiki/James_Edwin_Webb [wikipedia.org]
To 1-up wikipedia. Look, NASA!http://www.jwst.nasa.gov/whois.html [nasa.gov]
The man whose name NASA has chosen to bestow upon the successor to the Hubble Space Telescope is most commonly linked to the Apollo moon program, not to science.
Yet, many believe that James E. Webb, who ran the fledgling space agency from February 1961 to October 1968, did more for science than perhaps any other government official and that it is only fitting that the Next Generation Space Telescope would be named after him.

If the political will to feed the starving was here, we could do so and still put up the telescope. We spend the cost of the telescope a year on farm subsidies to prevent farmers from growing more crops. But the powers that be don't really give a shit.

Shuttle range wont really matter. They're retiring the fleet. I'm not sure if it will be in Ares I range or not, but it will surely be in Ares V range. The one thing I worry about on the whole Ares/Orin setup. The shuttle wasn't the best of designs for a lot of things, but one thing it was - it was a good work platform. Going back to capsules is great for a lot of reasons, but I do think an Ares V work platform module would be a good idea. Maybe even Ares I launchable fuel containers. I'll run that p

Haven't they had like several missions to fix Hubble? It seems like half the shuttle missions in the 90s were for that purpose.
I don't see how they are going to make this work if they can't service it. It will just end up being a waste of money.

The original test of the hubble mirror - which would have caught the abberation - was scrapped for financial reasons. We could have tested it on the ground, but got talked out of it for a few tens of thousands of dollars.

FWIW, I worked with one of the engineers who did optics design and testing, and knew most of the team working at Perkin Elmer - what I know about Hubble is mostly second hand, but from a reliable source.

Big Bang was no explosion, it was the expansion of space. The shape of space is a question that's been open to some discussion, but you should not assume that the light got away and is sitting on the "edge" somewhere (or expanding the edge), because there is no such edge. Also, during much of the initial period of the universe's existence, it was opaque -- the energy levels of matter were high enough that just about any EM radiation was continuously absorbed and re-emitted, giving us the background radiation.

The most important aspect here might also be the fact that space expansion is a local event. On a large enough "distance", the speed of that event, if we just tried to add together the relative expansion per unit length, would exceed c. It can certainly approach it. There is/should be matter much farther away than the 2 * 15 bly "bubble" that would be the theoretical maximum of matter simply going in all directions at the point of Big Bang.

On a large enough "distance", the speed of that event, if we just tried to add together the relative expansion per unit length, would exceed c.

That's certainly news to me! In fact, if you understood the concept of Special Relativity [wikipedia.org], this is precisely the concept that it excludes i.e. there can be nothing that moves faster than c. I would go into explaining how this all works and why there is no luminiferous aether [wikipedia.org] and Michelson-Moreley experiment [wikipedia.org] and how it lead to the development of Special Relativity but it would be way outside of the scope of what I can describe here.

There is/should be matter much farther away than the 2 * 15 bly "bubble" that would be the theoretical maximum of matter simply going in all directions at the point of Big Bang.

I don't think you understand the Big Bang Theory [umich.edu]. It postulates that all ma

Well, I'm guessing if you talk to the right Time Lord, he'll tell you were he placed a mirror a long ways off just before the big bang so that you can point at it with a telescope and in turn see the birth of the universe in its reflection.

The FLRW metric starts with the assumption of homogeneity and isotropy. It also assumes that the spatial component of the metric can be time dependent. The generic metric which meets these conditions is
...
where k describes the curvature and is constant in time, and a(t) is the scale factor and is explicitly time dependent, and natural units are used in which the speed of light is set to unity.

Well, the JWST hasn't really just been announced. I saw this model when I went to the SPIE conference several months ago. JWST itself has been in the planning stages for years. It was originally called NGST.